Methanogenesis and Salt Tolerance Genes of a Novel Halophilic Methanosarcinaceae Metagenome-Assembled Genome from a Former Solar Saltern

Anaerobic archaeal methanogens are key players in the global carbon cycle due to their role in the final stages of organic matter decomposition in anaerobic environments such as wetland sediments. Here we present the first draft metagenome-assembled genome (MAG) sequence of an unclassified Methanosarcinaceae methanogen phylogenetically placed adjacent to the Methanolobus and Methanomethylovorans genera that appears to be a distinct genus and species. The genome is derived from sediments of a hypersaline (97–148 ppt chloride) unrestored industrial saltern that has been observed to be a significant methane source. The source sediment is more saline than previous sources of Methanolobus and Methanomethylovorans. We propose a new genus name, Methanosalis, to house this genome, which we designate with the strain name SBSPR1A. The MAG was binned with CONCOCT and then improved via scaffold extension and reassembly. The genome contains pathways for methylotrophic methanogenesis from trimethylamine and dimethylamine, as well as genes for the synthesis and transport of compatible solutes. Some genes involved in acetoclastic and hydrogenotrophic methanogenesis are present, but those pathways appear incomplete in the genome. The MAG was more abundant in two former industrial salterns than in a nearby reference wetland and a restored wetland, both of which have much lower salinity levels, as well as significantly lower methane emissions than the salterns.

Eco-hydrology as a driver for tidal restoration: Observations from a Ramsar wetland in eastern Australia

Land reclamation projects and the installation of drainage infrastructure has impacted coastal wetlands worldwide. By altering water levels and inundation extent, these activities have changed the viable ecosystems onsite and resulted in the proliferation of freshwater species. As more than 50% of tidal wetlands have been degraded globally over the last 100 years, the importance of this issue is increasingly being recognised and tidal wetland restoration projects are underway worldwide. However, there are currently limited sites where large-scale reintroduction of tidal flushing has been implemented with the explicit aim to foster the growth of a threatened ecosystem. In this study, the tidal restoration of an internationally recognised Ramsar listed wetland in eastern Australia is described to highlight how coastal saltmarsh can be targeted by mimicking inundation depths and hydroperiod across the 410-ha site. Coastal saltmarsh is particularly important to this site as it is part of the east Australasian flyway for migratory birds and the minimum saltmarsh extent, as listed within the Ramsar’s limits of acceptable change, have been breached. To recreate coastal saltmarsh habitat onsite, water level and hydroperiod criteria were established based on similar vegetation patterns within the adjacent estuary. A calibrated 2D hydrodynamic model of the site was then used to test how the preferred inundation criteria could be applied to the largest possible restored wetland area. Once optimised, a synthetic tidal signal was implemented onsite via automated hydraulic controls. The onsite vegetation response over an 8-year period was assessed to highlight the ecosystem response to controlled tidal inundation and denoted substantial saltmarsh expansion during the period. The techniques applied onsite have successfully met the restoration targets and can be applied at similar sites worldwide, offsetting sea level rise impacts to natural inundation hydroperiod.

Evaluating the Floral and Avian Communities of an Ohio Wetland at The Wilds: 7 Years After Restoration

Wetland restorations have become an important tool in ecosystem management and have contributed to stabilizing hydrology and nutrient cycles, increasing native plant cover, and improving water quality. Long-term monitoring is essential for evaluating the success of a wetland restoration. However, wetland restorations are often monitored for short time periods compared to the timescale on which some abiotic factors change. Vegetative and avian assessments were conducted for a partially restored wetland on a reclaimed mine site, located at The Wilds® in Cumberland, Ohio. These assessments were performed from June through August 2018, 7 years after the initial restoration, using the unrestored portion as a comparison to evaluate restoration effectiveness. The restored wetland is characterized by open water with emergent vegetation, whereas the unrestored portion is largely a dense cattail (Typhus spp.) stand with low levels of standing water. The vegetative surveys used the Ohio EPA's Vegetation Index of Biotic Integrity for Emergent Vegetation (VIBI-E) and the bird surveys used a modified point count method. VIBI-E data are available for the study wetland from 1 year before restoration until summer 2018, while the avian study represents the first bird point count survey in the 2 wetland categories. The year 7 VIBI-E score of the restored section was the highest it has been since the restoration occurred and indicated "good" quality based on Ohio EPA scoring. The year 7 VIBI-E of the unrestored section has not changed since monitoring started and indicated "restorable" quality. The bird surveys showed higher richness associated with the restored wetland areas. These results demonstrate both the ecological value of wetland restoration and the ability for wetland restoration to maintain the ecological benefits over several years.